openssl: update URL

Closes #25335.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
diffpdf: Update homepage URL

diffpdf is going commercial, but version 2.1.3---the last
open-source one---is still available.  Its homepage has changed.

Closes #25341.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>